You are not your user, so stop designing for yourself. Understanding what your users need and communicating that around the organisation is super important.
It's often easier to break big problems down into smaller problems, which is one of the benefits of the agile process.
Sometimes you need to slow down to speed up.
Design can provide a huge amount of value to business.
Designers and technologists need to stop seeing themselves as separate from "the business".
The key role in any design or technology team is the lead role. They set the standards others follow, act as coaches and role models to juniors, while having the trust and ability to influence business stakeholders.
Everybody is largely trying to do the right thing.
It's better to design the right thing, than design the thing right.
It's easier to sell a well designed product than a poorly designed one. As such, more of the money you were going to send on marketing should be diverted into design.
In short, marketing should support product. Not the other way around.
Product management is the hardest job in tech.
The reason most projects go wrong is because of a lack of shared understanding from the outset.